When a child’s permanent tooth emerges behind a baby tooth that has not yet fallen out, parents often become concerned about the unusual double row of teeth. This common occurrence is informally known as “shark teeth.” While the nickname can sound alarming, the phenomenon is usually a manageable stage of dental development. Understanding this process and knowing when professional intervention is required can help guide the permanent tooth into its intended position. Correction does not always require braces, but treatment depends on how far the new tooth has deviated from its correct path.
Defining Shark Teeth
Shark teeth occur because the permanent tooth fails to follow the typical eruption path. Normally, the permanent tooth dissolves the root of the primary tooth above it through a process called root resorption, causing the baby tooth to loosen and fall out. When the permanent tooth grows at a slight angle, usually toward the tongue, it misses the primary root entirely. Since the primary tooth remains firmly in place, the permanent successor is forced to erupt behind the existing arch, creating the visual appearance of two rows of teeth. This event is most common around age six, when the lower front teeth (mandibular incisors) begin to emerge, but it can also occur later, around 11 to 12 years of age, as the permanent molars come in.
The Initial Clinical Intervention
In the majority of cases, the first course of action is a period of observation often referred to as “watch and wait.” If the primary tooth is slightly mobile, dental professionals encourage the child to gently wiggle it to promote natural exfoliation. Once the baby tooth is gone, the body’s natural anatomy plays a significant role in self-correction. The pressure exerted by the tongue pushes outward against the teeth, acting as a natural orthodontic force to gradually guide the permanent tooth forward into the space.
However, if the baby tooth remains completely firm for an extended period, such as two months after the permanent tooth has visibly erupted, extraction is recommended. This straightforward procedure immediately creates the necessary space, allowing the tongue’s pressure to begin the repositioning process. Timely removal is important to prevent the permanent tooth from becoming locked in a severely misaligned position far behind the dental arch. Extraction maximizes the chance of the permanent tooth migrating forward and aligning itself without the need for additional mechanical assistance.
Correcting Alignment with Braces
Braces are generally introduced only if the permanent tooth has erupted so far out of position that the tongue cannot push it into the correct arch alignment. Orthodontic treatment is also necessary if the retained primary tooth was a symptom of a larger underlying issue, such as severe crowding or a discrepancy in jaw size. This early treatment, often called interceptive orthodontics or Phase I treatment, is typically initiated between the ages of six and twelve, while the jaw is still developing.
The goal of this early intervention is to guide the permanent teeth into a more favorable position and address any skeletal issues that could complicate later alignment. This can involve the use of partial braces, applied only to the affected teeth, to move the tooth labially (outward) into the arch. Specialized appliances, such as a palatal expander, may also be used if a narrow upper jaw is contributing to crowding.
The appliances gently move the tooth over time, ensuring it is properly seated within the dental arch and that the patient achieves a correct bite relationship. For less severe malpositions, clear aligners may be an option to apply the necessary pressure. By addressing the position of the permanent tooth early on, interceptive treatment can significantly reduce the complexity or duration of comprehensive orthodontic treatment required during the teenage years.